unvarying

Synonyms

changeless, constant, stable, stationary, steady, unchanging;

Antonyms

capricious, changeful, changing, fickle, fluctuating, fluid, inconstant, mercurial, skittish, uncertain, unpredictable, unsettled, unstable, unsteady, varying, volatile;

Near Antonyms

adaptable, alterable, changeable, flexible, mutable, variable;

ephemeral, evanescent, fleeting, momentary, transient, transitory;

kaleidoscopic, phantasmagoric (or phantasmagorical);

Related Words

fast, fixed, hard-and-fast, immutable, inflexible, invariable, unalterable, unchangeable;

established, set, settled;

ceaseless, continuing, durable, enduring, lasting, permanent;

Phrases

on an even keel (also on even keel);